12-15 July 2011
Saint George Hotel
Africa/Johannesburg timezone

Brillouin scattering study of TiC hard films

14 Jul 2011, 08:30


Oral Presentation Track A - Condensed Matter Physics and Material Science CMPMS1


Mr Clemence Sumanya (DST/NRF Centre of Excellence in Strong Materials)


The dispersion relation of surface acoustic waves in TiC thin hard films of various thicknesses on silicon and silicon carbide substrate is studied using Surface Brillouin scattering. Simulations of surface Brillouin scattering (SBS) spectra of TiC thin hard films on silicon and SiC substrates have been carried out over a range of film thickness from 5nm to 1000nm. The simulations are based on the elastodynamic Green's function method that predicts the surface displacement amplitudes of acoustic phonons. These simulations provide information essential to understand and analyze experimental data emerging from SBS experiments. There are striking differences in both the simulated and experimental SBS spectra depending on the respective elastic properties of the film and the substrate. In fast on slow situations (TiC on Silicon), the Rayleigh mode is accompanied by broadened resonances; in slow on fast situations (TiC on SiC), several orders of Sezawa modes are observed together with the Rayleigh mode and sharper resonances. The velocity dispersion of the modes as a function of the product of surface wavevector and thickness (k//d) has also been simulated and obtained experimentally, allowing the elastic constants of the films to be determined.

Level (Hons, MSc, <br> &nbsp; PhD, other)? PhD
Consider for a student <br> &nbsp; award (Yes / No)? Yes
Would you like to <br> submit a short paper <br> for the Conference <br> Proceedings (Yes / No)? No

Primary author

Mr Clemence Sumanya (DST/NRF Centre of Excellence in Strong Materials)


Prof. Arthur Every (Materials Physics Research Institute, University of the Witwatersrand) Dr Bhekumusa Mathe (DST/NRF Centre of Excellence in Strong Materials) Dr Daniel Wamwangi (DST/NRF Centre of Excellence in Strong Materials) Prof. Darrell Comins (DST/NRF Centre of Excellence in Strong Materials) Mr Kudakwashe Jakata (DST/NRF Centre of Excellence in Strong Materials)

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